Make Heads or Tails of It
by Supervillegirl
Summary: Fourth in my Tail series. Picks up a week after "Tails of a Feather." Sherlock learns how to be a merman.


Make Heads or Tails of It

"All right, now, focus," said Dr. John Watson. "Just reach out and let instinct take over."

Sherlock Holmes stared down at the glass of water on the sitting room table, raising his hand towards it. John's explanation of how he was supposed to use his powers wasn't exactly helpful. It did nothing to tell him what he actually had to do.

 _Let instinct take over,_ Sherlock thought. _What kind of advice is that?_

Sherlock threw all his focus onto the glass of water, willing the water to move. He tried shaping his hand as he had seen John do when _he_ employed this specific power. But no matter how hard he tried, the water would not move.

"All right, all right," John finally said, putting his hands up to stop him. "Why don't you stop before you give yourself an aneurysm?"

Sherlock lowered his hand. "How do you make this look so easy?"

"The same way you make deductions look so easy; I've had twenty years of practice," John replied. "And it's also why I knew you would have trouble with this."

"You did?" asked Sherlock with a frown. "Why?"

"Because you're in your head too much," said John.

Sherlock's frown deepened.

"This isn't something that you can just give instructions for," John further explained. "There's no how-to manual; you can't think your way through it." He sighed as he thought for a moment and then looked apologetically at his friend. "For lack of a better Sherlock-friendly explanation, it's something you feel in your heart, your soul. My advice to you is to get out of your head and just _feel_."

Sherlock sighed, resisting the urge to roll his eyes. _That's easy for someone who isn't a self-proclaimed high-functioning sociopath to say._

Nevertheless, he turned back to the glass of water and tried to heed John's advice. It didn't work. Every time he tried to let down his mental barriers to let the heart he had not freed in over twenty years out, something in his mind panicked and refused to let it happen. Finally, Sherlock dropped his arm, closed his eyes and took a breath. Then he did what he had not done since he was a child. He released the mental hold he kept over his mind. He ignored the panic and pushed through it, releasing the firm control he kept over his emotions. As he did, a wave of voices and images sprung out of his mind palace.

" _Come on, Redbeard!"_

 _Old gravestones with funny dates…_

" _Play with me, Sherlock!"_

 _A young boy with an eye patch…_

" _I that am lost…"_

 _A house burning in the night…_

" _Sixteen by six, brother…"_

 _A young girl in pigtails running on the beach…_

" _The East Wind…"_

"Sherlock?"

Sherlock opened his eyes and looked at John. John was now standing in front of him and frowning, the concern clear in his eyes. It wasn't until then that Sherlock realized he wasn't breathing. His lungs released, and he gasped in a breath, inhaling deeply several times as his heart pounded.

"Hey, hey," said John quickly, grabbing onto his arms. "Take it easy."

Sherlock took a moment before speaking. "I'm fine."

"You sure?" asked John.

Sherlock nodded. "Yes."

John eased his hands off of Sherlock's arms. "What happened there?"

Sherlock reflected back on the random images and disjointed phrases that had come upon him. _What_ _ **had**_ _happened?_ "It's probably nothing. I haven't 'gotten out of my head,' as you put it, for decades. I suppose I was overwhelmed."

John sighed, appearing relieved. "Yeah, that's emotions for you. Do you need a moment before we try again?"

"No, I'm fine," said Sherlock, turning back to the glass. He took a breath before raising his hand.

He tried not to think and to just feel. And there it was. It was like an untapped well just waiting for an outlet. He opened his eyes and directed that well towards the glass. A column of water burst from the glass, rising into the air. It formed a twisting tentacle almost, before dropping back into the glass.

"Excellent!" said John. "Ready to try something else?"

* * *

 **One week later…**

"So, outside of baths, you haven't tried swimming or anything?" asked John as they walked through the night.

"Not yet," said Sherlock. "I didn't want to until I could dry myself off quickly afterwards. And hide myself, if I had to."

"Well, you have been missing out," John told him. "There's nothing like it."

They turned the corner and approached the river's edge. With it being the middle of the night, there was hardly anyone out and about in this area of London, but they weren't going to take any chances. As they prepared to leave the shadows and trusting Mycroft to keep the CCTV cameras distracted—because _of course_ he had known—they each made themselves invisible. When they reached the edge of the embankment, they came to a stop.

"Ready?" John asked from somewhere to his right.

"I suppose," Sherlock answered, not keen on jumping into the Thames with his tailored suit and heavy wool coat on, no matter how many times he had seen that John's clothes were dry when he transformed back.

"See you under the Thames," said John.

There was a rustle, and the sound of shoes scraping on pavement before a splash appeared on the surface of the river below him. Sherlock glanced around, but the noise hadn't attracted any attention. He held up the hand not maintaining his invisibility, staring at it. Or, more accurately, searching the air in front of him where his hand should have been. He chuckled a little as he shook his head. He still wasn't used to that.

Sherlock lowered his hand and stared down at the water before throwing himself off the edge. He hurtled through the air forty feet before plunging into the cold water. He could feel the pull of his water-logged coat as he tried to ignore the cold of the river. Several seconds later, it no longer mattered. He felt the transformation sweep over him. Suddenly, the river wasn't cold anymore. It felt…welcoming, warm.

Sherlock looked up through the surface of the water and then glanced around until he saw John floating some twenty feet away, staring in his direction. Sherlock looked at John and his tail—

 _It looks so different than it does from the surface._

-and then he dropped his invisibility. John's gaze moved to him, looking him up and down before smiling and jerking his head in a "follow me" gesture. He then turned and set off through the water, his tail pumping up and down like a dolphin's.

Sherlock looked down at his blue and white tail, giving it a few experimental pushes before he set off after John. He caught up to him and drew alongside, marveling at how he still didn't really need to come up for air yet.

John glanced over at him and then pointed up towards the surface some distance away. Sherlock nodded, deciding to trust him as he followed John off through the water. If Sherlock knew the streets of London better than anyone, John would know its waterways better than anyone. John brought them over under the dock of a ferry, and they surfaced.

"What do you think?" John asked.

Sherlock gave a shrug. "It's interesting."

John rolled his eyes. "Should've known it would take longer to convince you. Come on. I'll take you to the moon pool."

"The moon pool you transformed in?" asked Sherlock. "That's over seven hundred kilometers."

John smirked. "I know." He took a breath and went back under.

Sherlock grinned, sensing John had something up his sleeve. He dove back into the water, following the merman tail ahead of him as John swum to the center of the river and waited. Sherlock joined him and then watched as John placed his hands together in front of him, arms outstretched, smiled at Sherlock with a mischievous glint in his eyes and then disappeared in a cloud of bubbles. Sherlock turned his head to see John's trail of bubbles in his wake as he sped away almost too fast for him to see.

Sherlock shook his head in amazement before he took off after John.

Thirty minutes later, John was leading him through an underground river on the coast of Ireland. Just as Sherlock began to wonder if they would run out of air, the passageway turned upwards and then opened up into a pool. Sherlock broke the surface next to John and looked around. It looked very different from his own moon pool.

Whereas the moon pool in America had been in the center of a cave with a worn hole in its ceiling, this moon pool almost seemed to have been designed into this place, as though it was a dormant volcano. The pool itself was much wider than the other. It was surrounded by five feet of sand, and the walls led fifty feet up to a large hole in the ceiling. Through it, Sherlock could see the edge of the half moon above them.

Sherlock glanced over as John moved to the edge of the water, resting his arms on the edge and leaning back against it. He moved over to join his friend.

"Do you feel it?" asked John.

Sherlock stopped his observation of the pool and looked at the doctor. John's eyes were closed as he bathed in the inexplicable peace of this place.

"The magic?" said John.

Sherlock scoffed. "There's no such thing as magic. This is simply a science which mankind doesn't yet understand."

John slowly looked over at him. "Sherlock, in here…there's no such thing as science."

Sherlock looked up towards the moon, sensing that John just might be right. He _could_ feel the magic.

* * *

 **One week later…**

"Look, just solve the bloody thing," muttered Detective Inspector Lestrade. "None of us can figure it out." He stepped into the store and turned to face the doorway.

Sherlock stepped into the doorway, staring at the scene. The clothing store had mannequins knocked over, shirts askew on their hangers and glass shards from broken jewelry cases in the back of the store. Interestingly, there were greyish-black lines two feet long every two or three feet. Sherlock frowned and squatted down just inside the door, taking out a penknife to scrape at one of the lines. The knife scraped through to the white floor, and Sherlock lifted the knife to look at the black tendrils that had scraped off.

 _Rubber soles…_ Sherlock glanced up at the pattern of lines. _Skate brakes. Why skates?_

"Sherlock," he heard John's voice behind him.

"Hmm?" mumbled Sherlock vaguely.

"It's starting to rain," John told him.

"Oh," said Sherlock, standing quickly and moving to the side so John could come inside.

"You find anything yet?" John asked, gesturing to the marks on the floor.

"Not sure," said Sherlock, turning and heading towards the broken jewelry cases. "Nothing was taken?"

"The manager took an inventory himself," said Lestrade, following behind him. "Twice."

Sherlock examined the cases and then glanced around, trying to determine the path of the skates. One mark drew close to the door of the back office. He moved in that direction and started searching the office; it had a shredder.

"Yes!" Sherlock hissed as he moved to the drawers and started looking.

"What?" asked John.

"They have a paper shredder," Sherlock told him. "Most stores need to shred applications for credit cards. And a credit card application needs…"

"A National Insurance number," said John. "That's what they did?"

Sherlock found a file stuffed haphazardly back into the file folders, and he smirked as he pulled out a small stack of credit card applications. "They made it appear as though there had been a robbery. The owner would be so grateful nothing had been stolen—probably assuming the alarm had spooked them—that they wouldn't look into anything else. Meanwhile, the suspect is free to steal identities."

Sherlock made his way out of the office with the stack in hand. "Tell the owner to contact these customers." He handed the stack to Lestrade. "Their identities have been compromised. That's why nothing was taken." He stared towards the door. You'll find the suspect at the local skatepark. Approximately five feet two inches tall. She'll most likely be the one panicking at the sight of the police."

"She?" asked Lestrade.

Sherlock turned back at the door. "She may not have taken anything, but she definitely left something behind." He brandished a small bracelet at him before tossing it to him. He then turned, drawing his "forcefield" up, and headed out into the rain.

Not far down the road, Sherlock and John had taken shelter in an Underground Station, deciding to take the Tube until they were closer to Baker Street to save their strength.

"You know what I've noticed the last two weeks?" John pointed out in a hushed voice. "You haven't once used your new powers to solve crimes."

"Where would be the fun in that?" Sherlock replied. "Most crimes are too easy as it is. If I made them even easier, I would never have anything to do."

"Oh, God forbid," laughed John.

"John, have you ever come across any others?" Sherlock suddenly asked.

John looked over at him as they came to the gates, lowering his voice. "What, other mermen?"

"Yes," said Sherlock, pulling his Oyster card from the pocket of his coat.

"Not until you, no," John answered, swiping his own Oyster card and stuffing it back in his wallet as he walked through the gate.

"Any mer _maids_?" asked Sherlock.

"No, never," John replied as they stepped onto the escalator.

"Seems odd," muttered Sherlock. "To have been swimming the waters of England for twenty years and not come across another. We can't be the only two in the country."

John shrugged. "Maybe we are."

"Statistically unlikely," Sherlock replied. "There has to be more somewhere."

* * *

 **Sorry if I didn't get the UK National Insurance number correct. I have no idea if it's as tightly controlled as a US Social Security Number. But for my story, you can steal an identity with a National Insurance number.**


End file.
